Magnetocaloric effect in W-doped Ni–Mn–Sn alloy probed by direct and indirect measurements

Abstract

In the present work, the influence of W-doping instead of Ni and Sn on the structural and martensitic transformation (MT) characteristics, magnetic behavior and inverse magnetocaloric effect (MCE) exhibited by Ni47Mn40Sn13 metamagnetic shape memory alloys (metaMSMAs) has been investigated. The inverse MCE in the vicinity of MT was measured: (i) by the indirect method using thermomagnetization curves and temperature dependence of heat capacity, and (ii) by the direct measurements of the field-induced adiabatic temperature changes, ΔTad. It is found that both methods revealed ΔTad values which are in a good agreement with each other. The results of direct method show the largest MCE at MT for Ni46W1Mn40Sn13 alloy (the maximum absolute values of 2.2 K for a magnetic field change of 1.96 T) if compared to the other two alloys. The outcomes demonstrate that doping by W is an efficient tool to tailor properties of the Ni–Mn–Sn MCE alloy, which is a promising material for the magnetic refrigeration.